A compound meant to mimic the effects of natural cannabinoids was found to reverse the short and long-term deficits caused by repeated social defeat in a new study published by the journal Neuropsychopharmacology.

Psychosocial stress contributes to the development of psychiatric disorders. Repeated social defeat (RSD) is a murine stressor that causes a release of inflammatory monocytes into circulation. Moreover, RSD-induced anxiety-like behavior is dependent on the recruitment of these monocytes to the brain.

With this in mind, it’s important to note that “Activation of the endocannabinoid (ECB) system [done naturally through the consumtion of cannabinoids] may modulate both neuroendocrine and inflammatory responses mediated by stress”, states the study’s researchers. “Therefore, we hypothesized that a cannabinoid receptor agonist would attenuate RSD-induced inflammation, anxiety, and stress sensitization.”

To test this hypothesis, “mice received an injection of the synthetic cannabinoid1/2 receptor agonist, WIN55,212-2 (WIN; 1 mg/kg, intraperitoneally) daily for six consecutive days, 30 min before each exposure to RSD. Anxiety-like behavior, immune activation, neuroinflammation, and microglial reactivity were determined 14 h[ours] after RSD.”

RSD-induced anxiety-like behavior ” was reversed by WIN55,212-2″. Moreover, “WIN55,212-2 reduced the accumulation of inflammatory monocytes in circulation and brain after RSD and attenuated RSD-induced interleukin-1β (IL-1β) messenger RNA (mRNA) expression in microglia/macrophages. Increased ex vivo reactivity of microglia/monocytes to lipopolysaccharides (LPS) after RSD was also attenuated by WIN55,212-2.”

Next, “fear expression, extinction, and recall were evaluated 24 and 48 h, respectively, after contextual fear conditioning, which took place 7 days after RSD. Here, RSD caused prolonged fear expression and impaired fear extinction recall, which was associated with increased IL-1β mRNA in the brain.” Moreover, “these stress-induced effects were reversed by WIN55,212-2.”

The study concludes by stating that “activation of cannabinoid receptors limited the immune and neuroinflammatory responses to RSD and reversed the short-term and long-term behavioral deficits associated with RSD.”

Anthony Martinelli

Anthony is co-founder and Editor-in-Chief of TheJointBlog. He has worked closely with numerous elected officials who support cannabis law reform, including as the former Campaign Manager for King County (WA) Councilmember Dave Upthegrove. He has been published by multiple media outlets, and is a former contributor for Village Voice Media.